Apparatus for coating sheet material



Feb. 2, 1943.

c. J. RANDALL v APPARATUS FOR COATING SHEET MATERIAL 2 Sheets-Sheet lmmvrba 66 5976? u. FAA/041A A mRNEYS.

Filed Nov. 30; 1939 Feb. 2, .1943. c. J. RANDALL I APPARATUS FOR COATINGSHEET MATERIAL 2 Sheets-Sheet 2 Filed NOV. 30. 1939 INVENTOR/ 095575?FAA/041A BYM a A TTORNEYS.

STATES: PATENT orms 1 l l d' llsg o i rmc SHEET I I Chester J. Randall,Naugatuck, Conn., assignor to United States Rubber Company, New York, N.Y., a corporation of New Jersey 2 Application November 30, 1939, SerialNo. 306,817 scisime. (oral-4s) This invention relates to an apparatusfor applying liquids, par icularly rubber containing liqulds, to sheetmaterials, such as textile fabrics. for the purpose of coating and/orimpregnating such materials.-

Heretofore fabrics have been coated by applying the rubber containingliquid to the surface thereof by the use of the doctor blade method,

by theuseof the usual pickup roll which runs in a bath of the liquid andcarries it to the surface of the fabric running in contact therewith,

and by coating a surface, such as a belt, with f th rubber containingliquid and then applying the fabric to the coated surface andtransferring the liquid coating thereto. In all of the above named[methods it is dimcult; to control the amount of liquid applied to thesurface of the fabric. Consequently the thickness of the coating ofrubber deposited on the fabric and the degree of penetration of theliquid cannot be accurately controlled. The last named method of coatingfabrics also resultsin the loss of the rubber containing liquid due to'some of it sticking to the belt after the fabric has been removed. Thecontrol of the thickness of the coating and the penetratio of the rubbercontaining liquid by the above methods becomes increasingly moredifilcult in the treatment of light weight materials, such as knitted orwoven fabrics.

In accordance with the present invention the rubber containing liquid isapplied directly to the fabric under an hydraulic head which transmitsthe liquid to all surfaces of the fabric under a uniform pressure whichcan be accurately controlled by controlling the quantity of liquidsupplied, and thereby uniformly coat or penetrate the surface of thefabric to the predetermined extent desired. I

The above and other objects of this invention will be more clearlyunderstood byreferring to the following description and the accompanyingdrawings, in which:

Fig. '1 is a semi-diagrammatic side elevation of the complete apparatus;

Fig. 2 is a semi-diagrammatic plan view thereof 4 Fig. 3 is a section online 3--3 of Fig. 1;

Fig. 4 is a view of .a section of an applier bar taken in perspectivefrom above; and

Figs. 5, 6 and 7 are cross-sectional views of the coated fabricillustrating, respectively, a light coating, and difierent degrees ofpenetration pro duced by the rubber containing liquid.

Referring to Fig. 1 of the drawings, the sheet material III or fabric tobe coated, is led from areel ll underneath a pair of rollers l2 and I3which are supported on a table l4. The material I is drawn from the rolll3 up one side of an applier bar I and down the other side by a driven'roll l6. As the material is drawn over the bar IS a liquid, suchas arubber containing liq- .uid, adapted to produce'a coating on the fabricwhen dried is forced from the interior of the applier bar and applied tothe under surface of the material 10. The cylindrical surface of theroll [6 is covered with a material adapted to resist the slippage of thefabric thereon. As shown in the drawings, the cylindrical surface of theroll I6 is covered with what is commonly known as card clothing materialhaving relatively small, sharp and, closely spaced pins anchored in afabric backing which is placed adjacent to the roll so that the pinsproject from the periphery of the roll and contact with the materialIll. sheet material It passes from the roll l6 over a roll I! and thenover a heating surface I8, where the coating is dried. The sheetmaterial It! is supp rted over the heating surface 18 by a pluralityofsmall rolls 19. The coated material It] then passes underneath a roll 20and is wound up Three samples of the finished. coated fabric,impregnated different amounts, are shown in Figs. 5, 6 and '7. As shownin Fig. 5 the finished rabric 22 consists of a, light, coating 23 ofrubber composition applied to the fabric II]. In this case the fabric ispenetrated to a very small extent. Fig. 6 illustrates a finished fabric24 having a coating of rubber 25 which penetrates the fabric It) toabout one-half its thickness, and Fig. '7 illustrates a fabric 26 inwhich the textile fabric It) has been completely penetrated and providedwith a coating 21.

The coatings of rubber 23, 25 and 21 in Figs. 5, 6 and 'l are depositedupon the under surface of the fabric l0 from a rubber containing liquidwhich is applied to the fabric by means of the applier bar l5 which isshown in detail in Figs. 3 and 4. The applier bar l5 has a transverselyrounded upper surface which is provided with a longitudinal groove 28over which the fabric is drawn by the driven roll l6 and held in contactwith the edges of the groove by the roll I3 and the driven roll [6. Therubber containing liquid is supplied to an internal chamber 29 in theapplier bar IS. The chamber 29 is connected with the groove 28 by arestricted throat 30 which extends substantially the length of thegroove 28 and causes back pressure to be built up in the chamber 38 andevenly distributes the The rubber containing liquid under a uniformpressure throughout the length of the groove 28. The hydraulic pressureplaced upon the rubber containing liquid in the chamber 29 is socontrolled that the groove 28 is completely filled with the rubbercontaining liquid at all times. The liquid is thereby continuouslymaintained in contactwith the bottom surface of the fabric I as it isdrawn over the bar I5. An undercut groove 3| is formed in the applierbar l and it is provided with an upper edge 32 which extends along theline where the fabric breaks contact with the upper surface of the bar.The top surface of the edge 32 extends substantially parallel with, ortangentially to, the bottom surface of the fabric and prevents therubber containing liquid from pulling away from and stringing after thefabric as it leaves the top surface of the bar IS.

The rubber containing liquid is supplied to the bar l5 from a tank 33which is connected .to a pump 34 through a pipe 35. Thepump 34 deliversthe rubber containing liquid through a pipe 36 and its branches 3'!(Fig. 3) to the chamber 29 in the bar l5, and thence to the groove 28.For the purpose of insuring a free flow of rubber containing liquid fromthe tank 33 to the pump 34, air under the desired pressure is suppliedto the top of the rubber containing liquid in the tank'33 through a pipe38.

The hydraulic pressure or the quantity of rubber containing liquiddelivered to the groove 28, in a unit of time is controlled by the speedat which the pump 34 is driven, and the quantity of rubber containingliquid applied to the unit area of the fabric ID as it passes over theapplier bar l5, for a given rate of fiow of liquid, is controlled byvarying the speed at which the fabric I0 is drawn over the bar l5. Forthis purpose the roll I6 is driven by a motor 39 which drives thevariable speed drive 40 through a sprocket and chain drive 4|. Thevariable speed drive 40 is connected to the shaft 42 of theroll l6 bymeans of a sprocket and chain drive 43. The speed at which the fabric isdrawn over the bar l5 by the roll I 6 may be controlled by varying theratio of the driving to the driven speeds in the variable speed drive 40by means of the hand wheel 44.

The pump 34 is driven through a variable speed drive 45 on the oppositeside of the machine from the variable speed drive 40. The variable speeddrive 45 is driven from the shaft 42 of the roll l6 through a sprocketand chain drive 46. The variable speed drive 45 is directly connected tothe pump 34 through the sprocket and chain drive 41. The speed of thepump 34 and consequently the rate of flow of rubber containing liquidand the hydraulic pressure maintained thereon may be varied by changingthe ratio of the driving to the driven speeds in the drive 45 byoperating the hand wheel 48.

Wherever the term rubber containing liquid is used herein it shallinclude rubber cements and suitably compounded latex which latterbroadly designates coagulable aqueous dispersions of elastic materials,including artificial dispersions of rubber or rubber-like materials aswell as natural latex, which may be preserved or compounded or otherwisetreated as desired, as by vulcanization, and which may be in a normal,diluted,

' bar having a transversely rounded upper surconcentrated or'purifledcondition produced by methods well known in the art.

As shown herein the pump 34 is of the rotary type which produces auniform flow of liquid without pulsations. Such pump is suitable forpumping rubber cement but as is well known it is not suitable forpumping rubber containing liquids, such as latex, which-coagulate uponthe blades of the pump. Where it is desired to use latex in.this systemthe pump 34 is taken out of the pipe line 35 and 36 and the tank 33 isdirectly connected to the chamber 29 in the applier bar I 5 by the pipes35 and 36. Sufilcient air pressure is applied through the pipe 38 to thetop of the latex in the tank, and the pressure is controlled in any wellknown manner to cause the latex to fiow'at a predetermined rate to thebar l5.

While this invention has been described in detail it will be understoodthat changes may be made, and it is desired to claim the invention asbroadly as permitted by the prior art and as covered by the scope of theappended claims.

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

1. An apparatus for applying liquid to the surface of sheet materialcomprising a support for said material, said support having atransversely rounded upper surface provided with a groove extendinglengthwise thereof, means for drawing the material across said grooveand in contact with the edges thereof on said support, said roundedsurface having an undercut groove therein provided with a top edgeextending parallel with said groove and along the line where the sheetmaterial breaks contact with the surface of the support, and means forsupplying said groove with liquid so as to maintain the liquidcontinuously in contact with the material.

2. An apparatus for applying liquid to the surface of sheet materialcomprising an applying face provided with a groove extending lengthwisethereof, a roller on each side of the said bar so arranged that thematerial passes underneath the rollers and over the bar and is therebymaintained in contact with the edges of said groove, means for pumpingliquid into said groove, means for controlling thequantity of liquidpumped, means for drawing said material underneath said rollersandoversaid bar, and said pumping means being driven from said drawing means sothat any change in speed of said drawing means will cause a proportionalchange in the speed of said pumping means.

3. An apparatus for applying liquid to the surface of sheet materialcomprising an applicator for said material, said applicator having atransversely rounded surface provided with a groove extending lengthwisethereof, means for drawing the material across said groove and incontact with the edges thereof on said applicator, said rounded surfacehaving an undercut groove therein provided with an edge extendingparallel with said groove and along the line where the sheet materialbreaks contact with the surface of the applicator, and means forsupplying said groove with liquid so as to maintain the liquidcontinuously in contact with the material.

CHESTER J. RANDALL.

